This project will investigate the role of specific bacterial tRNA's in regulating biosynthetic pathways. We shall continue to investigate the role of tRNATrp in regulating expression of the trp operon at the attenuator site. We also shall investigate a possible role of tRNA's in the "stringent" response which regulates synthesis of ribosomal components according to the availability of amino acids. Other aspects of this project are designed to identify the regions of tRNA structure most critical for 1) tRNA processing, 2) recognition by aminoacyl tRNA synthetases, and 3) ribosomal binding.